Page 1 of 1

piezo operation and efficiency

Posted: Sat Apr 22, 2017 8:11 pm
by Mark Wybierala
I'm still on the ubass investigation and I'm looking at piezos. I've seen contact piezos for sale and don't fully understand the principle as compared to the typical undersaddle piezo which seems to make more sense. In an undersaddle piezo, the piezo is under the downward force of the saddle and string vibration is efficiently transferred to the piezo film sandwiched between the conductive materials. When there is a defect in the contact area, such as the bottom of the saddle not being flat or debris in the saddle slot, one or more strings can suffer from significantly lower output even to the point of becoming nearly silent out of the preamp. I've seen very slight defects cause a significant problem. These contact piezo pickups which are sometimes single or multiple piezos in parallel, just stick to the surface of the top or bridge with an adhesive. Are they just more sensitive or are they inferior to the efficiency of an undersaddle piezo?

The current project/distraction involves a 1/2 size cello with a 23" scale and I'm thinking about installing a set of ubass strings on it to see what happens and what the result is like. I need a piezo. I have a lot of undersaddle piezos on hand and I probably could fabricate a bridge with a corian saddle in a slot if the undersaddle piezo set up is better. Or, I could get a pair of piezo pads to go under the feet of the bridge. I think I also still have some piezo cable. I feel that piezo material under string pressure would be more effective providing more string tone reproduction vs body noise reproduction compared to these contact piezos. Either way, I'll be using an active preamp.

Thoughts and discussion???

Re: piezo operation and efficiency

Posted: Sun Apr 23, 2017 12:33 pm
by Barry Daniels
I feel that the K&K Pure Mini contact pickups are a step in from undersaddle piezo pickups. They don't even require a pre-amp but you can use one to boost the output.

Re: piezo operation and efficiency

Posted: Tue Jun 27, 2017 7:18 am
by Andy Bounsall
I have JJB contact pickup (same as K & K, but lower price) on one of my guitars and am very pleased with how it sounds. As Barry said, you can use these pickups with or without a preamp.